.text
.global _start

_start:
	/*配置输入输出*/
	ldr r1, =0x56000050
	ldr r0,=0x100
	str r0,[r1]
	
	/*设置电平*/
	ldr r1, =0x56000054
	ldr r0,=0x00
	str r0,[r1]
	
/*死循环*/
halt:
	b halt
	
	